As the population continues to age, the number of elderly patients who are candidates for surgery will rise dramatically. Many of them will derive quality and length of life benefits from their surgery. Others will experience complications, placing them at higher risk for discharge to a nursing home, an outcome associated with an increased risk for death. Better understanding of factors influencing outcomes following surgery is important for two reasons. First, it can help guide candidacy for elective surgery by identifying patients in whom the risks of surgery likely exceeds the benefits. Second, improved risk predictions can identify patients in whom interventions designed to improve outcomes may be indicated. Endothelial progenitor cells (EPCs) are a subtype of adult stem cell that appear to protect against cardiac and cerebrovascular arteriosclerotic disease through their ability to generate endothelium and neovascularize ischemic tissues. These two actions are likely to have importance in patients undergoing surgery in that cardiac ischemia induced by surgery is a precipitant of myocardial infarction. Our study will extend previous observations regarding EPC's role in cardiovascular disease by determining whether EPC's are associated with risk for postoperative myocardial infarction. We propose a 2 year prospective trial of 125 patients undergoing vascular surgery at UCSF Medical Center, in whom we will collect pre-and postoperative data regarding EPC count and function, determine the incidence of cardiac events using clinically objective measures (e.g. ECG and Troponin-l), as well as detecting additional post-discharge events through phone follow-up at 1 and 6 months. Our study's results will give a greater knowledge of the pathophysiology of recovery following major noncardiac surgery, yield understanding of how EPC's may be used - along with traditional risk indices - to aid risk stratification, as well as guide the development of future observational and clinical trials of preventative strategies using EPCs as a therapeutic modality. [unreadable] [unreadable] [unreadable]